DNA derivatized with n-butylamine has previously been shown by Hanlon and her colleagues to have the distinctive circular dichroism spectrum which has been repeatedly associated in the literature with the C form of DNA. Earlier studies from this lab questioned the basis of that assignment. Consistent with our conclusions in those studies, our current results in a joint study with Dr. Hanlon indicate that DNA derivatized with n-butylamine has a B form in fibers at high relative humidity or in wetted fibers using x-ray fiber diffraction methods.